This seems to be the way of it now: just a few days after the last Community Day, Pokémon GO developer Niantic Labs has announced the special Pokémon for April's event. The next Community Day rolls around on April 15. It's a step up from Bulbasaur, mostly because it has a higher base capture rate and is rarer, overall. It's also possible Niantic is trying to avoid hurting the combat balance, but combat is useless anyway, so that argument doesn't really hold. Community Day could be better deployed, but it's still a fun time.

Source: Forbes March 27, 2018 19:07 UTC